Magnetically dynamic damping assembly

ABSTRACT

An assembly for magnetically dynamic damping useful for isolating vibrational forces includes a housing wall bounding a main chamber therein. The assembly further includes a fixed magnetic source disposed in the main chamber. A diaphragm of elastic material is disposed in the assembly impermeably dividing the main chamber into sub-chambers. The diaphragm includes a magnetically actuated element adjacent to the fixed magnetic source. A source of electrical current energizes the magnetically actuated element, the fixed magnetic source, or both and either repels or pulls the magnetically actuated element with respect to the fixed magnetic source. A magnetic guide surrounds the fixed magnetic source and defines a gap exposing the fixed magnetic source to the magnetically actuated element. The magnetic guide routes the magnetic field towards the gap and prevents outward magnetic interference to the rest of the assembly.

CROSS REFERENCE TO RELATED APPLICATION

This U.S. Utility patent application claims the benefit of and priorityto U.S. Provisional Patent Application Ser. No. 62/556,924 filed Sep.11, 2017, the disclosure of which is incorporated herein by reference inits entirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention is generally related to dampers. Moreparticularly, the present invention relates to an assembly formagnetically dynamic damping useful for isolating vibrational forces.

2. Description of the Prior Art

Conventional damping assemblies are used for isolating vibrationalforces and are particularly useful in automobiles which are oftensubject to an array of vibrational loads. Damping assemblies are oftentimes utilized between an engine and a chassis of an automobile forinsulating both environmental vibrations such as driving over a bumpyroad and internal vibrations such as the idling of the engine. Theseassemblies include chambers that provide rebound when under increasedpressure. Many damping assemblies incorporate partitions that include adecoupler having an elastic diaphragm which impermeably divide a chamberinto sub-chambers. When one of the sub-chambers is subjected toincreased pressure, the diaphragm flexes into the other sub-chamber,passively stifling vibrational forces. In this regard, diaphragms areparticularly useful for isolating the second type of vibrations, engineidling. A modern trend has been to incorporate elements to switchdecouplers between active and inactive conditions for situations inwhich passive damping is unwanted. One example is illustrated in U.S.Pat. No. 5,246,212 to Funahashi et al., wherein a damper is utilized inan automobile and includes a vacuum source for depressurizing one sideof the divided chamber pulling the diaphragm until it is held in aflexed condition such that it can no longer passively dampen vibrations.Another example illustrated in U.S. Pat. No. 9,022,368 which involvesapplying electricity through a ferromagnetic diaphragm that switches thediaphragm between a ridged and flexible condition. However, a commonshortcoming of these prior damping units is the inability to tunedamping force requirements of the decoupler between more than just anactive and an inactive condition. Particularly in situations in whichdampening is required but to a lesser or greater extent, which could bea result of varying amplitude and frequency of vibrations, the prior arthas failed to provide a satisfactory dynamic decoupler.

SUMMARY OF THE INVENTION

The invention provides for a magnetically dynamic damping assemblyuseful for isolating vibrational forces. The assembly includes a housingwall bounding a main chamber with a fixed magnetic source disposedtherein. A diaphragm of elastic material is disposed in the assemblyimpermeably dividing the main chamber into sub-chambers. The diaphragmincludes at least one magnetically actuated element adjacent to thefixed magnetic source. A source of electrical current energizes themagnetically actuated element, the fixed magnetic source, or both andeither repels or pulls the magnetically actuated element with respect tothe fixed magnetic source. A magnetic guide surrounds the fixed magneticsource and defines a gap exposing the fixed magnetic source to themagnetically actuated element. The magnetic guide routes the magneticfield towards to gap and prevents outward magnetic interference to restof the assembly.

The assembly provides increased tuning in a damping assembly whilepreventing magnetic interference in certain applications. Inenvironments where variable dampening is required, which may depend onthe amplitude or frequency of vibrations, the subject invention providesfor variable flexibility and movement of the diaphragm. Movement of thediaphragm is dependent on the strength of the magnetic field that thediaphragm is exposed to. Furthermore, in applications where magneticinterference is unwanted, such as a magnetorheological fluid damper, themagnetic guide routes the magnetic field directly to the diaphragm andprevents exposure of the magnetically actuated fluid to the magneticfield.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present invention will be readily appreciated,as the same becomes better understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings wherein:

FIG. 1 is a cross-sectional view of an example embodiment of the dampingunit in an non-energized condition wherein a diaphragm is free to flex.

FIG. 2 is a cross-sectional view of the example embodiment of thedamping unit in an energized condition wherein the diaphragm isrestrained from movement by a magnetic force.

FIG. 3A is a cross-sectional view of one embodiment of the subjectinvention utilizing a moving coil and a fixed permanent magnet.

FIG. 3B is a cross-sectional view of another embodiment of the subjectinvention utilizing the moving coil and a fixed induction coil.

FIG. 3C is a cross-sectional view of yet another embodiment of thesubject invention utilizing an annular moving magnet and the fixedinduction coil.

FIG. 3D is a cross-sectional view of another embodiment of the subjectinvention utilizing a plurality of block-shaped moving magnets and thefixed induction coil.

FIG. 4 is an enlarged cross-sectional view illustrating the connectionof a decoupler to the damping unit.

FIGS. 5A-5C are graphical representations of the embodiment illustratedin FIG. 3A wherein the fixed permanent magnet and the moving coil areutilized.

FIGS. 6A-6C are graphical representations of the embodiment illustratedin FIG. 3B wherein the fixed induction coil is utilized with the movingcoil.

FIGS. 7A-7C are graphical representations of the embodiment illustratedin FIG. 3C wherein the fixed induction coil is utilized with a singleannularly shaped moving magnet.

FIGS. 8A-8C are graphical representations of the embodiment illustratedin FIG. 3D wherein the fixed induction coil is utilized with a pluralityof block shaped moving magnets.

DESCRIPTION OF THE ENABLING EMBODIMENT

Example embodiments will now be described more fully with reference tothe accompanying drawings. The subject embodiments are directed to amagnetically dynamic damping assembly. However, the example embodimentsare only provided so that this disclosure will be thorough, and willfully convey the scope to those who are skilled in the art. Numerousspecific details are set forth as examples of elements to provide athorough understanding of embodiments of the present disclosure.Referring to the Figures, wherein like numerals indicate correspondingparts throughout the several views, a magnetically dynamic dampingassembly constructed in accordance with the subject invention isgenerally shown in FIGS. 1 and 2.

The magnetically dynamic damping assembly includes a damping unit 20,generally shown in FIGS. 1 and 2, having a housing wall 22 ofcylindrical shape extending about an axis A between a base portion 24and a top portion 26 bounding a main chamber 28 therein. A barrier 30 isspaced between the base portion 24 and the top portion 26 and dividesthe main chamber 28 between a base sub-chamber 32 and a top sub-chamber34. The barrier 30 typically extends perpendicularly to the axis Acentrally between the base portion 24 and the top portion 26. Apartition 36 is disposed in the main chamber 28 and includes an internalholding wall 38. The internal holding wall 38 extends radially about theaxis A and includes a first section 40, a second section 42, a thirdsection 44, and a fourth section 46 divided by steps wherein eachsubsequent section extends radially outwardly from the preceding sectionat a step. The first section 40 defines an isolation chamber 48 having agenerally cylindrical shape. The second section 42 extends radiallyoutwardly from the first section 40 to defining a bottom bearing holdingspace. Subsequently, the third section 44 extends radially outwardlyfrom the second section 42 to define a decoupler holding space. At thenext step, the fourth section 46 extends radially outwardly from thethird section 44 to define a top bearing holding space. A bottom bearingring 52 includes a bottom bearing rib 54 and sits on the step betweenthe first and second sections 40, 42 and is pressed into the secondsection 42. A decoupler 50 sits on the next step and is pressed into thethird section 44 impermeably separating the isolation chamber 48 fromthe main chamber 28. A top bearing ring 56 includes a top bearing rib 58and sits on the last step pressed into the fourth section 46.

The decoupler 50, generally indicated in FIGS. 1-4, has a disk shape.The decoupler 50 includes an outer ring 60 having an annular shape thatdelimits a flexible diaphragm 62. The outer ring 60 provides both axialand radial support of the diaphragm 62 and extends axially between a topring side and a bottom ring side. An outermost edge of the outer ring 60can be sized to engage the third section 44 of the internal holding wall38 in a press-fit connection. The outer ring 60 has a cross section thatdefines a circular outer portion 64 extending inwardly to a neck portion66 extending inwardly to a holding portion 68. The holding portion 68 isconnected to and retains the diaphragm 62. The outer ring 60 is thickerthan the diaphragm 62 such that the diaphragm 62 is disposed between andspaced from the top ring side and the bottom ring side. When assembled,the neck portion 66 is disposed adjacently between the bottom bearingrib 54 and the top bearing rib 58 for retaining the circular outerportion 64 in the third section 44 while allowing some axial flexing ofthe outer ring 60. Thus, when the main chamber 28 is placed underpressure, the assembly allows elastic displacement of the diaphragm 62towards or away from the isolation chamber 48.

As best illustrated in FIGS. 3A through 4, in order to provide dynamicrebound properties to the decoupler 50, the partition 36 includes afixed magnetic source 70 that is utilized to employ a magnetic fieldwhen it is in an energized state. The fixed magnetic source 70 includesan outer side, facing the housing wall 22 of the damping unit 20 and aninner side facing the isolation chamber 48. The decoupler 50 includes amagnetically actuated element 72 embedded therein and extending axiallytherefrom to define a diaphragm rib 74. A magnetic guide 76 extendsaround the fixed magnetic source 70 for retaining the magnetic field.The magnetic guide 76 includes a sleeve 78 that is placed over the outerside of the fixed magnetic source 70 and a core 80 that is disposed onthe inner side of the fixed magnetic source 70. The sleeve 78 and core80 are disposed such that the entire fixed magnetic source 70 issurrounded except a small gap 82 between the sleeve 78 and the core 80facing the diaphragm rib 74 of the decoupler 50. In one embodiment, thesleeve 78 includes an annular sleeve wall 84 extending to a sleeve lip86 that extends perpendicularly, radially inward therefrom. The core 80includes an annular core wall 87 extending to a core lip 88 extendingradially outwardly therefrom. The sleeve 78 and core 80 guide themagnetic field into the gap 82, orienting it with the decoupler 50, andpreventing magnetic interference outside of the partition 36. Themagnetically actuated element 72 reacts to the employed magnetic field,where the axially extending diaphragm rib 74 is either pulled into thegap 82 or pushed away from the gap 82. A non-magnetic insert 90 (shownin FIG. 4) is placed under the magnetically actuated element 72 toprovide radial and axial support and align the magnetically actuatedelement 72 during the push and pull movement. The insert 90 isnon-magnetic and does not interfere with the magnetic operation of thepartition 36 and may also rerout the magnetic field back towards the gap82.

In one embodiment, illustrated in FIG. 3A, the magnetically actuatedelement 72 includes a moving coil 72 a embedded in the diaphragm 62. Themoving coil 72 a extends annularly around the center of the diaphragm 62to form a ring shape rib 74 protruding axially. The moving coil 72 a hasa deenergized state and an energized state and is connected to a sourceof electrical current 94 for switching between states. In a preferredembodiment, the moving coil 72 a is over molded into the diaphragm 62and includes approximately 200 turns. This embodiment also utilizes thenon-magnetic insert 90 (shown in FIG. 4), having an annular shape thatis embedded in the diaphragm 62. The non-magnetic insert 90 includes athinner portion 96 and a wider portion 98 divided by an axial step. Thenon-magnetic insert 90 provides support for the moving coil 72 a withoutbeing affected by the magnetic field. The moving coil 72 a is disposeddirectly above the thinner portion 96 and adjacent to the step. Thefixed magnetic source 70 includes at least one permanent magnet 70 aplaced along the first section 40 of the internal holding wall 38between the core 80 and the sleeve 78. In a preferred embodiment, the atleast one permanent magnet 70 a includes one ring-shaped magnet; howevermultiple magnets could be used. The permanent magnet 70 a creates amagnetic field that is guided by the core 80 and sleeve 78 into the gap82. As the moving coil 72 a is energized, a current is formed that caneither draw or repel the moving coil 72 a with respect to the the gap 82depending on the direction of current flowing into the moving coil 72 a.During operation, the non-magnetic insert 90 remains unaffected by themagnetic field and keeps the moving coil 72 a in axial alignment withthe gap 82, rerouting the magnetic field and preventing some magneticinterference outside of the magnetic guide 76. The graphicalrepresentation of FIG. 5A illustrates the rerouting of the magneticfield by the magnetic guide 76, and includes a legend indicating thestrength of the magnetic field along areas of the magnetic guide 76 andgap 78. FIGS. 5B and 5C are graphical representations of the movingcoil's 72 a position, which is dependent on the strength of the inducedmagnetic field as a function of amount of current provided.

In another embodiment, illustrated in FIG. 3B, the magnetically actuatedelement 72 still includes a moving coil 72 a embedded in the diaphragm62 and a non-magnetic insert 90 as set forth above. However, the fixedmagnetic source 70 includes a fixed induction coil 70 b placed along thefirst section 40 of the internal holding wall 38 between the core 80 andsleeve 78. The fixed induction coil 70 b is wrapped around a bobbin 100for several turns and is electrically connected to a source ofelectrical current 94. In one preferred embodiment, the fixed inductioncoil 70 b has more turns that the moving coil 72 a. In one exampleembodiment, the fixed induction coil 70 b has approximately 410 turns.Current variations in the induction coil 70 b and the moving coil 72 adraw and repel the moving coil 72 a from the gap 82 dependent on thedirection of the current through the induction coil 70 b and the movingcoil 72 a. When a fixed induction coil 70 b is used, the magnetic guide76 may define one or more apertures for allowing a wire to extendtherethough and form an electrical connection between the fixedinduction coil 70 b and the source of electrical current 94. A graphicalrepresentation in FIG. 6A illustrates the rerouting of the magneticfield by the magnetic guide 76, and includes a legend indicating thestrength of the magnetic field along areas of the magnetic guide 76 andgap 78. FIGS. 6B and 6C are graphical representations of the movingcoil's 72 a position, which is dependent on the strength of the inducedmagnetic field as a function of amount of current provided to both themoving coil 72 a and the fixed induction coil 72 b.

In yet another embodiment, illustrated in FIG. 3C, the magneticallyactuated element 72 includes at least one moving magnet 72 b. The atleast one moving magnet 72 b is typically includes one magnet having anannular shape corresponding to the shape of the gap 82 between thesleeve 78 and the core 80. The moving magnet 72 b constantly provides amagnetic field. Because this magnetic field is always present, the fixedmagnetic source 70 of this embodiment is a fixed induction coil 70 b sothat there are not always two interacting magnetic fields. Accordingly,as the fixed induction coil 70 b is charged, the fixed induction coil 70b creates a magnetic field and pulls the movable magnet into the gap 82or pushes it away from the gap 82. A graphical representation in FIG. 7Aillustrates the rerouting of the magnetic field by the magnetic guide 76when one annular moving magnet 72 b is utilized, and includes a legendindicating the strength of the magnetic field along areas of themagnetic guide 76 and gap 78. FIGS. 7B and 7C are graphicalrepresentations of the annular moving magnet's 72 b position, which isdependent on the strength of the magnetic field as a function of amountof current provided to the fixed induction coil 72 b.

In another embodiment, illustrated in FIG. 3D, the magnetically actuatedelement 72 includes a plurality of block magnets 72 c. The block magnets72 c are arranged on the diaphragm 62 in a correspondingly annular shapeof the gap 82 between the sleeve 78 and the core 80. Much like thepreceding embodiment, the block magnets 72 c constantly provides amagnetic field. Because this magnetic field is always present, the fixedmagnetic source 70 of this embodiment is a fixed induction coil 70 b sothat there are not always two interacting magnetic fields. Accordingly,as the fixed induction coil 70 b is charged, the fixed induction coil 70b creates a magnetic field and pulls the block magnets 72 c into the gap82 or pushes them away from the gap 82. A graphical representation inFIG. 8A illustrates the rerouting of the magnetic field by the magneticguide 76 when block magnets 72 c are utilized, and includes a legendindicating the strength of the magnetic field along areas of themagnetic guide 76 and gap 78. FIGS. 8B and 8C are graphicalrepresentations of the block magnets' 72 c position, which is dependenton the strength of the magnetic field as a function of amount of currentprovided to the fixed induction coil 72 b.

The damping unit 20 in a preferred embodiment includesmagnetorheological fluid (MR fluid). Barriers 30 of damping units 20utilizing MR fluid typically define flow paths 102 extending between thetop sub-chamber 34 and the base sub-chamber 32. As one of thesub-chambers 32, 34 are subjected to added pressure due to vibrationalforces, the MR fluid is squeezed from the pressurized sub-chamber to theless-pressurized sub-chamber. In order to tune the amount of pressurethat transfers MR fluid between sub-chambers 32, 34, and the rate inwhich the MR fluid flows, solenoids 104 are disposed adjacent to theflow paths 102. When the solenoids 104 are provided with a current, amagnetic field is created that extends around the flow paths 102. WhenMR fluid is exposed to a magnetic field, magnetic particles in the MRfluid align increasing viscosity and thereby becoming more resistant tosqueezing through the flow path 102. In this manner, certain reboundcharacteristics of the MR damper can change with the amount of currentsupplied through the solenoid 104.

In addition to guiding the magnetic field of the fixed magnetic source70, the magnetic sleeve 78 and core 80 also prevent flow pathinterference by rerouting and localizing the magnetic field away fromthe flow paths 102. In accordance with this functionality, the magneticfield created by the solenoid 104 is the only magnetic field thatinteracts with the MR fluid. Stated another way, the pushing and pullingof the decoupler 50 does not affect the viscosity around the flow paths102 and the solenoid 104 does not affect the pushing and pulling of thedecoupler 50.

In operation, the source of electrical current 94 could provide currentto either end of the wrapped fixed induction coil 70 b or moving coil 72a. As a result, the poles of the magnetic field created could bereversed, thus pushing instead of pulling. Furthermore, the currentcould be scaled based on necessity. On one end of the scale, no currentwould be provided, and thus the diaphragm 62 would flex unencumbered. Onthe other end of the scale, maximum current would be provided to thefixed induction coil 70 b, the movable coil, or both. When maximumcurrent is provided, a strong magnetic field is generated and the rib 92of the diaphragm 62 is pulled completely into the gap 82 and thediaphragm 62 is restrained from vibration, i.e., dampening. In themiddle of the scale, a medium amount of current can be provided whichrestricts some movement of the rib 92 relative to the gap 82, but stillallows the diaphragm 62 to retain a certain amount of flexibility. Thesource of electrical current 94 can be electrically connected to acontroller, such as a CPU 106 that would include programming torecognize a threshold frequency or amplitude of vibrations and provideenough current to have optimal damping from the decoupler 50. The CPU106 recognized threshold could also be the rate of pressure change inone or more of the sub-chambers 32, 34. The CPU 106 could then signalthe source of electrical current 94 to provide a certain amount ofcurrent in a certain direction in the fixed induction coil 70 b of themoving coil 72 a, ultimately providing a smoother ride to both a driverand passengers.

It should be appreciated that in the multiple embodiments describedherein that the partition 36 is integrated into the barrier 30 andextends along the axis A. However, the partition 36 can be offset fromthe axis A and define an isolation chamber 48 anywhere within thedamping unit 20. The isolation chamber 48 may be open to the atmosphereor completely closed off. Likewise, the vibrational forces do not needto be along the axis A, ultimately the decoupler 50 responds to thechanging pressure of any chamber it divides. Additionally, it should beappreciated that the magnetic guide 76 and non-magnetic insert 90 couldcomprise any number of suitable materials. For example, these elementscould comprise materials with high magnetic permeability that reroutethe magnetic field, specifically, the magnetic flux. As just a fewnon-limiting examples, these materials could include cobalt-iron,permalloy, and many other suitable materials that ideally combine highmagnetic permeability with low weight.

Obviously, many modifications and variations of the present inventionare possible in light of the above teachings and may be practicedotherwise than as specifically described while within the scope of theappended claims. Antecedent recitations should be interpreted to coverany combination in which the inventive novelty exercises its utility.The use of the word “said” in the apparatus claims refers to anantecedent that is a positive recitation meant to be included in thecoverage of the claims whereas the word “the” precedes a word not meantto be included in the coverage of the claims. In addition, the referencenumerals in the claims are merely for convenience and are not to be readin any way as limiting.

What is claimed is:
 1. A magnetically dynamic damping assemblycomprising; a damping unit including a housing wall extending between abase portion and a top portion bounding a main chamber therein, apartition including a diaphragm of elastic material disposed in saiddamping unit impermeably dividing said main chamber into sub-chambers,said diaphragm including at least one magnetically actuated element,said partition further including a fixed magnetic source for creating amagnetic field adjacent to said at least one magnetically actuatedelement, a source of electrical current including an energized conditionwherein said source of electrical current provides current to saidpartition creating a magnetic field regulating said at least onemagnetically actuated element of said diaphragm relative to said fixedmagnetic source and a non-energized condition wherein said source ofelectric current does not provide current and said diaphragm isunrestricted to flex as a result of pressure changing in one of saidsub-chambers.
 2. An assembly as set forth in claim 1 wherein saidpartition includes a magnetic guide surrounding said fixed magneticsource defining a gap exposing said fixed magnetic source to saidmagnetically actuated element and guiding said magnetic field towardssaid gap.
 3. An assembly as set forth in claim 2 wherein saidmagnetically actuated element extends axially from said diaphragm todefine a surface rib extending towards said gap and wherein said surfacerib is contoured to enter said gap in said energized condition.
 4. Anassembly as set forth in claim 3 wherein said diaphragm further includesa non-magnetic insert disposed therein and spaced under said at leastone magnetically actuated element to provide radial and axial supportand align said surface rib with said gap.
 5. An assembly as set forth inclaim 1 wherein said fixed magnetic source includes a fixed inductioncoil and said source of electrical current is electrically connectedthereto for providing current and creating said magnetic field.
 6. Anassembly as set forth in claim 5 wherein said at least one magneticallyactuated element includes a moving magnet.
 7. An assembly as set forthin claim 5 wherein said at least one magnetically actuated elementincludes a moving coil and said source of electrical current is alsoelectrically connected thereto for providing current independently tosaid moving coil and said induction coil to create interacting magneticfields.
 8. An assembly as set forth in claim 1 wherein said fixedmagnetic source includes a fixed permanent magnet creating said magneticfield and said at least one magnetically actuated element includes amoving coil electrically connected to said source of electrical currentactuating said moving coil to interact with said magnetic field createdby said fixed permanent magnet.
 9. An assembly as set forth in claim 2wherein said damping unit contains magnetorheological fluid and includesflow paths and a solenoid adjacent to said flow paths changing theviscosity of said magnetorheological fluid entering said flow paths. 10.An assembly as set forth in claim 3 wherein said non-magnetic insertincludes a stepped surface with a thinner portion spaced inwardly and awider portion spaced outwardly and wherein said at least onemagnetically actuated element is disposed on said thinner portion andsaid wider portion reroutes at least some lateral and axial outwardmagnetic interference from said gap back into said gap.
 11. Amagnetically dynamic damping assembly comprising; a damping unitincluding a wall extending between a base portion and a top portionbounding a main chamber therein, a decoupler including a diaphragm ofelastic material impermeably dividing said main chamber intosub-chambers, said diaphragm including at least one magneticallyactuated element that extends axially therefrom to define a surface rib,a fixed magnetic source for creating a magnetic field to draw and repelsaid at least on magnetically actuated element, a magnetic guidesurrounding said fixed magnetic source and defining a gap exposing saidfixed magnetic source to said at least one magnetically actuated elementwherein said magnetic guide contains and reroutes said magnetic fieldtowards said gap.
 12. An assembly as set forth in claim 11 wherein saidat least one magnetically actuated element defines an annular shape andsaid gap is outlined by a corresponding annular shape for allowing entryof said at least one magnetically actuated element.
 13. An assembly asset forth in claim 12 wherein said diaphragm further includes anon-magnetic insert having an annular shape disposed therein and spacedunder said at least one magnetically actuated element to provide radialand axial support and align said magnetically actuated element with saidgap.
 14. An assembly as set forth in claim 11 wherein said decouplerincludes an outer ring portion being more rigid than and delimiting saiddiaphragm providing axial and radial support to said diaphragm.
 15. Anassembly as set forth in claim 14 wherein said damping unit includes atop bearing ring and a bottom bearing ring and wherein said outer ringof said decoupler is sandwiched between said top bearing ring and saidbottom bearing ring.
 16. An assembly as set forth in claim 15 whereinsaid outer ring has a cross section defining a circular outer portionand a medial neck portion and an inner holding portion and wherein saidbearing rings each include bearing ribs extending on opposite sidestowards said neck portion of said outer ring for allowing some axialflexing of said neck portion while retaining said circular outerportion.
 17. An assembly as set forth in claim 11 wherein said magneticguide includes a sleeve and a core pressed together.
 18. An assembly asset forth in claim 17 wherein said sleeve includes an annular sleevewall extending to a sleeve lip that extends radially inwardly therefromand said core includes an annular core wall extending to a core lipextending radially outwardly therefrom.
 19. An assembly as set forth inclaim 12 wherein said at least one magnetically actuated element extendsaxially from said diaphragm towards said gap to define a surface rib onsaid diaphragm.
 20. An assembly as set forth in claim 11 wherein saiddamping unit contains magnetorheological fluid and includes flow pathsand a solenoid adjacent to said flow paths for changing the viscosity ofsaid magnetorheological fluid entering said flow paths.